Turbines may be used to generate power. A typical turbine may include a rotor associated with a number of wheels. The wheels may be spaced apart from each other along the length of the rotor and define a series of turbine stages. Turbine wheel spaces may be cavities or areas of a turbine located between the turbine rotor or wheels that support corresponding rows of turbine blades. The wheel spaces may be located radially inward of a mainstream flow of gas through adjacent turbine stages. Typically, the radially inward discs are heated by various effects, including conduction through the rotor blades, ingress of mainstream flow into the wheel space cavities, and windage heating within the wheel spaces.
Turbine wheel space temperatures may increase due to heating and may be related to turbine output, ambient temperature, and unit degradation or general condition. In some instances, wheel space temperatures may be higher than acceptable temperatures, causing operators to reduce turbine output to prevent excessive or high wheel space temperatures. To cool turbine wheel spaces, typically a purge system may be used to deliver a cooling flow to the wheel spaces and reduce the wheel space temperatures. However, due to size restrictions and turbine machinery structure, the cooling flow may not be delivered to the wheel spaces in an optimal manner.